Pneumatic actuator with electrical position detector

ABSTRACT

The invention consists of the combination of a pneumatic actuator part ( 1 ) and an electrical position detector part ( 2 ), the containing structures thereof sealingly combine along a contour edge ( 3 ), with the containing structure ( 8 ) of the electrical position detector part ( 2 ) contributing to implement the depression chamber ( 4 ) of the pneumatic actuator part ( 1 ) and inside thereof there is provided a small chamber ( 15 ) housing the resistive member ( 16 ), the thrust spring ( 19 ) and the head ( 17 ) of the sliding member bearing the electrical contacts ( 18 ) rubbing onto the resistance ( 16 ).

BACKGROUND OF THE INVENTION

[0001] The invention relates to a pneumatic actuator with electricalposition detector, apt for vehicles with internal combustion engines andin particular for adjusting and controlling the turbocompressors.

[0002] Pneumatic actuator devices combined with electrical positiondetectors of resistive type, utilized in the turbocompressors, areknown.

[0003] In such devices the pneumatic actuator group, usually workingunder depression, has the structure defining the depression chamber onone side equipped with a guide for sliding the extracting member, on theopposite side it is provided with a hole, with sealing gaskets,therethrough the head of said extracting member connects to the slidingstem of the resistive sensor of the electrical position detector. Theend of said sliding stem, in order to keep adhering to the head of theextracting member of the pneumatic actuator, is constantly pushed by aspring. The head of the sliding stem of the resistive sensor and saidspring are housed inside the casing of the electrical position detectorwhich is applied above the pneumatic actuator. Said head is equippedwith sliding guides and with flexible and elastic electric contactswhich are destined to rub onto a resistive film glued inside said casingof the electrical position detector so that the sliding of said headwith electric contacts determines the change in value of the resistancepart comprised between the output electrodes. The measurement of theresistance comprised between the output electrodes allows then to detectthe position of the rubbing contacts and therefore the position of theextracting member of the pneumatic actuator.

[0004] Such device, then, results to be constituted by the combinationof two distinct mechanisms: a pneumatic one and an electrical one. Suchcombination involves the mechanical assembly of two structures whichrequires a complex and therefore expensive intervention in changing andadapting the first structure, the pneumatic one. The two mechanisms areconnected between them through the structure delimiting the chamber ofthe pneumatic actuator working under depression or however under apressure different from the environmental one. Therefore, it isnecessary utilizing appropriate gaskets which cannot guarantee theperfect sealing and thus the correct operation of the first mechanism,that is the pneumatic actuator.

[0005] On the contrary, the position detector has the resistive film onthe inside thereof, which can wear quickly at high temperatures whereinthe combined system is made to operate, when it is utilized in theturbocompressors, therefore its long duration cannot be guaranteed.

SUMMARY OF THE INVENTION

[0006] An object of the present invention is to implement a pneumaticactuator device with electrical position detector which results to havea moderate cost and assured operation, even in presence of highpressures or depressions.

[0007] Another object is to implement a device which cannot be opened,then which is not subjected to tamperings and/or alterations outside thefirm manufacturing it.

[0008] Still another object is to implement a device with theincorporated electrical part apt to withstand even the hightemperatures, therefore which is able to guarantee a long duration.

[0009] At last, another object is to implement a device enabling to bemanufactured with smaller sizes than the ones of the corresponding knowndevices.

[0010] The invention which has allowed achieving such resultsconcretizes in the combination of a pneumatic actuator part and anelectrical position detector part, the containing structures thereofsealingly combine along the contour edge thereof. The containingstructure of the electrical position detector part implements the upperpart or “vault” of the depression chamber of the pneumatic actuator partand, inside thereof, it is equipped with a small chamber, closed by aplug on the lower side. Such chamber houses the resistive member, thethrust spring and the sliding member, the head thereof bears thecontacts rubbing onto the resistance and the stem thereof, once crossedthe plug, reaches the head of the extracting member of the pneumaticactuator part in order to move therewith.

[0011] Such device results particularly advantageous because itsstructure is relatively simple, it is very strong and thereforeresistant and it has a moderate cost. It is advantageous because itcannot be opened and, however, each intervention inside thereof leavestraces in the junction sealingly joining the two parts, therefore it canbe checked.

[0012] It is advantageous because the adjusting resistive member is amechanical structure apt to withstand even the high temperatures,therefore it guarantees a long duration even when the invention isutilized in the turbocompressors of the vehicles with internalcombustion engines.

[0013] Furthermore, it is advantageous because the whole structurethereof is compact and not much bulky.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Other advantages will be easily understood, particularly by theskilled persons working in the art, by reading the following detaileddescription related to the preferred embodiment solution, illustrated byway of example in the drawings of the enclosed figure wherein:

[0015]FIG. 1 is the prospective view of the invention;

[0016]FIG. 2 is the front view of the invention, sectioned with an axialplane;

[0017]FIG. 3 is the exploded front view of the electrical positiondetector part.

[0018] It is meant that the drawings are just exemplary in order to makeeasier the comprehension of the invention, without being a limitationtherefor.

DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

[0019] Substantially, therefore, the invention consists of a devicewherein two parts combine, one onto the other. The lower one is thepneumatic actuator part 1, the upper one is the electrical positiondetector 2. The two parts are implemented so that the containingstructure 9 of the pneumatic actuator 1 and the containing structure 8of the electrical position detector part 2 combine between them with ajoint 3, sealing along the contour edge. In such implementation thecontaining structure 8 of the electrical position detector part 2implements the upper part or “vault” of the depression chamber 4 of thepneumatic actuator 1. In the solution exemplified in the FIG. 2, thecontaining structure 9 of the pneumatic actuator part 1 on the top hasan edge directed towards the outside. The edge of the flexible sheath 5,inside the central part thereof the cup-like structure 6 is housed, onthe base thereof the extracting member 7 of the pneumatic actuator part1 is fastened, rests on such edge.

[0020] The containing structure 8 of the electrical position detectorpart 2 is shaped like a cup upside-down with respect to the containingstructure 9 of the pneumatic actuator part 1. The ending edge thereof isfolded towards the outside in order to rest on the edge of the flexiblesheath 5, therefore on the most inner part of the edge of the containingstructure 9 of the pneumatic actuator part 1. The edge of the containingstructure 9 is then folded towards the inside to compress and clamp theoverlapped edges of the containing structure 8 and of the flexiblesheath 5, until implementing the sealing joint 3. The containingstructure 8 of the electrical position detector part 2 and the flexiblesheath 5 originate the depression chamber 4 of the pneumatic actuator 1.Said chamber 4 communicates with the outside through the spout 10,placed on the containing structure 8 of the electrical position detectorpart 2. The containing structure 8 on the inside thereof also has thesurface 11, shaped like a circular crown, thereagainst the spring 12bucks. It opposes the sliding of the base of the cup-like structure 6inside the containing structure 9 of the pneumatic actuator part 1 when,through the spout 10, a depression is produced inside the chamber 4.

[0021] The containing structure 8 of the electrical position detectorpart 2 on the inside thereof has a small chamber 15 inside thereof thevariable resistance 16, the head 17 with the contacts 18 rubbing ontothe resistance 16 and the spring 19 opposing the sliding of said head 17are housed.

[0022] Said small chamber 15 is vantageously closed on the lower side bya plug 31 which is provided at least with a hole for the not-guidedsliding of the shaft 26 of the head 17 which is equipped with rubbingelectrical contacts 18. Said plug 31 can be provided with feet 32 forthe positioning and snap-locking thereof into the seat destined toreceive it or it can be fastened to said seat by welding, glueing andany other way.

[0023] The variable electrical resistance 16 is equipped with its ownmechanical structure and/or with a support with feet buried in the jet,that is it can be stabilized in the position destined thereto byco-molding with the casing 8 of the electrical position detector part 2.However, it has the surfaces at sight therethrough the electricalconnection with the rubbing contacts 18, integral to the head 17, isperformed.

[0024] At last, inside said chamber 15 advantageously there arelongitudinal grooves 21 for the positioning and the not-guided slidingat least of the head 17 equipped with contacts 18. All this to guaranteethe electrical contact of the contacts 18 themselves onto the resistance16 upon changing the position thereof inside the small chamber 15.

[0025] On the contrary, the spring 19 is sized to perform the thrustonto the head 17. The thrust is sufficient to keep inside the chamber 4the end of the shaft 26 in contact with the head of the extractingmember 7 of the pneumatic actuator part 1.

[0026] Upon the implementation, the manufacturing particulars could alsobe subject to variations, without altering the functional logique of theinvention, therefore with said variations being comprised within thescope of the invention as defined by the following claims.

1. A pneumatic actuator with electrical position detector to be used inthe vehicles with inner combustion engines and in particular inadjusting and controlling the turbocompressor, comprising a pneumaticactuator part (1) and an electrical position detector part (2),characterized in that the containing structure (9) of the pneumaticactuator part (1) and the containing structure (8) of the electricalposition detector part (2) sealingly combine between them along acontour edge (3) and in that the containing structure (8) of theelectrical position detector part (2) implements the “vault” of thedepression chamber (4) of the pneumatic actuator part (1).
 2. Thepneumatic actuator with electrical position detector, as claimed inclaim 1, characterized in that the containing structure (8) of theelectrical position detector part (2) has on the inside thereof a smallchamber (15) inside thereof the variable resistance (16), the head (17)with the contacts (18) rubbing onto the resistance (16) and the spring(19) positioned so as to oppose the sliding of said head (17) arehoused.
 3. The pneumatic actuator with electrical position detector, asclaimed in claim 1, characterized in that the small chamber (15) insidethe containing structure (8) of the electrical position detector part(2) is closed on the lower part by a plug (31) equipped at least with acentral hole for the sliding of the shaft (26) projecting from the head(17).
 4. The pneumatic actuator with electrical position detector, asclaimed in claim 1, characterized in that the containing structure (8)of the electrical position detector part (2) has the spout (10)therethrough it puts into communication the outside with the depressionchamber (4) of the pneumatic actuator part (1).
 5. The pneumaticactuator with electrical position detector, as claimed in claim 1,characterized in having a variable electrical resistance (16) withstructure with feet buried into the moulded jet therewith the casing (8)of the electrical position detector part (2) is implemented and with thesurfaces at sight therethrough the electrical connection with therubbing contacts (18) is implemented.
 6. The pneumatic actuator withelectrical position detector, as claimed in claim 1, characterized inthat in the small chamber (15), inside the containing structure (8) ofthe electrical position detector part (2), longitudinal grooves (21) areplaced for the positioning and the not-guided sliding at least of thehead (17) with the rubbing contacts (18).
 7. The pneumatic actuator withelectrical position detector, as claimed in claim 1, characterized inhaving a spring (19) sized so as to perform the thrust onto the head(17) sufficient to keep inside the chamber (4) the end of the shaft (26)in contact with the head of the extracting member (7).
 8. The pneumaticactuator with electrical position detector, as claimed in claim 1,characterized in that the containing structure (8) of the electricalposition detector part (2) on the inside thereof has a surface shapedlike a circular crown (11) thereagainst the spring (2) opposing thesliding of the cup-like structure (6) towards the containing structure(8) bucks when a depression is produced in the chamber (4).